Brake flush machine

ABSTRACT

A fluid-distribution system includes a plurality of fluid-distribution nodes with three-way ports attached to bleed/flush lines and alternate ports attached to vacuum lines. A first pump is used to draw new brake fluid from a new fluid container, push it through the manifold and ports, and through the bleed/flush lines. Fluid flow through the ports is selectively controlled by a computing device. In this manner, a vehicle&#39;s brake system including individual brake lines and ABS systems, may be flushed in a prescribed sequence. The vacuum lines are connected to a second pump via alternate ports of the sequential control valve manifold and may be used evacuated air and contaminated brake fluid from the vehicle&#39;s bleeder valves or master cylinder. Additionally, the bleed/flush lines may be connected to the alternate ports during priming or purging of the system. This also facilitates storage of the bleed lines as it prevents brake fluid from spilling and prevents air from entering the system.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/265,820, which was filed on Nov. 3, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is related in general to the field of automotivemaintenance systems. In particular, the invention consists of a brakeflush machine that allows sequential flushing of a vehicle's brake linesand anti-lock braking system (“ABS”).

2. Description of the Prior Art

Anti-lock brake system (ABS) design utilizes multiple hydraulicpassageways and valving that restricts fluid movement. This means thatfluid flowing through the system will be limited and may take excessivetime to properly flush the system. The pressure that can be exerted onthe system is limited by the master cylinder reservoir adapter. Theadapter connects the pressurized fluid from a brake flush machine to themaster cylinder reservoir to the brake system. Most reservoirs are acomposite or plastic material and cannot be exposed to pressures above20 psi without deforming the shape of the reservoir and causing leakage.Most brake flush machines limit master cylinder reservoir pressure to12-18 psi to prevent leakage. The low pressure also makes removing brakefluid contamination more difficult.

In addition, the fluid does not move through each wheel system equally,but it will take the path of least resistance. Some brake flush machinesflush all the wheels at the same time. A machine designed to flush allthe wheels at the same time may experience an unequal system flush. Thismeans that one part of the system may experience minimal fluid flow,which will not provide a proper flush.

Isolated flush machines isolate different parts of the system to controlfluid flow. This allows the machine to force fluid though the morerestrictive circuits. The downside is that the flush time is lengthenedbecause the flow is isolated to a part of the system and not all thewheels at the same time. A properly isolated flush could take 2-3 timeslonger to move the same amount of fluid as an all-wheel flush, keepingin mind that the all-wheel flush also experiences an unequal systemflush.

Empirical testing using Strip Dip7 brake fluid test strips has shownthat it takes approximately 2 gallon of brake fluid flushed equallythrough the system at sufficient pressure and flow to attain a properflush to remove contaminants. Most all wheel flush machines use 2 gallonfluid container and operate for 10-12 minutes. The last minute or two ofthe cycle removes whatever fluid is left in the container and dumps itinto the waste container so that the service uses 2 gallon of brakefluid each time. This does not mean the 2 gallon of brake fluid wasflushed through the system, but only that 2 gallon of brake fluid wasconsumed. The actual flush may have used 1 quart of fresh fluid and theother quart was dumped into the waste. The reason this is done is tocomplete the flush within the allotted time period and consume 2 gallonof brake fluid per service regardless of the quality of flush.

There is also a low/no pressure area in many master cylinder designsthat is isolated from the normal fluid pathway during a flush. Thisleaves an area of old fluid that can contaminate the new brake fluidafter the flush has been performed. Even if 2 gallon of brake fluid isflushed through the system, the isolated low pressure area cancontaminate the brake fluid once the brake pedal is depressed a fewtimes. Depressing and holding the brake pedal exposes the new fluid tothe low pressure area. This has been demonstrated again by the use ofFASCAR7 Strip Dip brake fluid test strips. A candidate vehicle wastested with Strip Dip7, demonstrating a FASCAR7 rating of 100. The brakeflush was performed using ½ gallon of brake fluid using propersequencing and isolation and the brake fluid was immediately testedafter the service, which results in a FASCAR7 rating of 0. The vehicleis then driven in which the brake pedal is depressed several timesduring normal braking and a Strip Dip7 retest is performed, whichresults in a FASCAR7 rating of 25. It is not a problem with the teststrip, but the low/no pressure area was not cleaned during the flushprocess and the old fluid contaminated the rest of the system.

To attain a proper brake system flush, approximately ½ gallon of brakefluid must be flushed through the system at sufficient pressure, circuitisolation, and flow to remove contaminates. In addition, the low/nopressure area of the master cylinder must be exposed to fluid flow toflush that portion of the system to prevent future contamination. Anisolated brake flush machine could take as long as 30 minutes toproperly introduce ½ gallon of brake fluid sequentially through thesystem, while current all wheel flush machines operate for 10-12 minutesand waste the unused fluid. Each brake flush machine design has severedesign flaws, first is the time to perform service or, second, thequality of the service performed.

There are different classifications and standards for brake fluid,D.O.T. 3, 4, 5, and 5.1 (synthetic). D.O.T. 3, 4, and 5.1 brake fluidscan be mixed together and perform to at least the minimum specificationof the primary fluid. The seals in the brake system are compatible withthese fluids. D.O.T. 5 is a silicone based fluid and cannot be mixedwith any other type of brake fluid and will void many original equipmentbrake part warranties if used in a vehicle. D.O.T. 5 is primarily usedfor off-road use like racing and in motorcycle brake systems.

In addition, there are several manufacturers of brake fluids in the sameD.O.T. class that have varying performance criteria. Many originalequipment manufacturers have their own formulation of brake fluid.Therefore, it is desirable to have a brake flush machine that can beused with various manufacturers' specifications of brake fluid. It istherefore important for the brake flush machine to be able to purge thebrake flush machine with fluid used in the last service and prime thebrake flush machine with the desired fluid for the next service. Thisfeature gives the user the ability to service a variety of vehicles eachwith the original equipment manufacturer's brand of brake fluid.

Most late model anti-lock braking systems (“ABS”) require the use of ascan tool to properly bleed and flush the brake system. There are nocurrent brake flush machines that allow the user to use a scan toolwhile the automated brake flush is performed. It is therefore desirableto have an interface which allows the user to perform variousbleed/flush tasks as prompted by the scan tool.

Accordingly, it is desirable to have a brake flush system that primesbrake fluid into a brake flush machine's bleed/flush lines in a mannerthat removes air and different types of fluid from these bleed lines andintroduces the correct type of brake fluid. Additionally, it isdesirable to have a system of sequentially flushing various bleed linesand ABS systems. It is also desirable to have an easy-to-use interfacesuch as a graphical user interface or combination of graphic symbols orletters, lights, lamps, LEDs, buzzers, and speakers. A method of quicklyconnecting and disconnecting bleed lines and preventing fluid fromflowing in the wrong direction is desirable as well. Other desirablefeatures include utilizing a dual-pump manifold system to pressurizesome fluid lines while providing vacuum on others; notifying a user whena low-flow, fluid empty, or system leak situation occurs; utilizing OEMscan tools such as GM Tech 2®; providing troubleshooting and diagnosticsfor the brake fluid machine; and performing reverse fluid injection,vacuum bleeding, pressure bleeding, and test-bench bleeding using thesame bleed lines.

SUMMARY OF THE INVENTION

The invention disclosed herein utilizes a fluid-distribution systemincluding one or more pumps, a plurality of fluid-distribution nodes, anonboard computer, and bleed/flush lines to sequentially flush avehicle's brake system. A purge cycle allows the brake flush machine toremove air, old fluid, or the wrong type of fluid from the machine'smanifold and bleed lines. The plurality of fluid-distribution nodesincludes solenoids that are controlled by the onboard computer thatallow for sequentially flushing of various bleed lines and the vehicle'sABS system, if present. Additionally, the fluid-distribution system iscapable of closed-loop priming with fluid for the next service.

A graphical user interface displays various information and may includea touch screen input device. Alternatively, a user interface may includea combination of graphic symbols or letters, lights, lamps, LEDs,buzzers, and speakers to communicate information to a technician.

Quick connect fittings are added to the bleed lines to allow the quickconnecting and disconnecting from bleed valves. An optional check valvein each bleed/flush line prevents fluid from flowing in the wrongdirection, preventing air or waste fluid from back-flowing into thevehicle's brake system.

A dual-pump sequential control manifold allows the system to pressurizesome fluid lines while providing vacuum on others, if desired. Thisdecreases the time necessary to flush the brake system and increases thebrake flush machine's ability to remove contaminants from the vehicle.

Another feature of the invention involves utilizing a notificationsystem of graphical screens, lights, lamps, LEDs, buzzers or speakers tonotify a user when a low-flow, fluid empty, or system leak situationoccurs. Yet another feature is an interface that allows thefluid-distribution system to utilize OEM scan tools such as GM Tech 2.5.Another aspect of the invention is a memory device for storing vehicleuser manuals or bleed sequences that may be displayed on the GUI. Theinvention also includes troubleshooting and diagnostics systems for thebrake fluid machine itself.

Various other purposes and advantages of the invention will become clearfrom its description in the specification that follows and from thenovel features particularly pointed out in the appended claims.Therefore, to the accomplishment of the objectives described above, thisinvention comprises the features hereinafter illustrated in thedrawings, fully described in the detailed description of the preferredembodiments, and particularly pointed out in the claims. However, suchdrawings, description, and claims disclose just a few of the variousways in which the invention may be practiced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a fluid-distribution systemincluding one or more pumps, a plurality of fluid-distribution nodes, anonboard computer, a user-interface, a waste receptacle, and a pluralityof bleed/flush lines.

FIG. 2 is a block diagram of a main menu of the user-interface of FIG.1.

FIG. 3 is a block diagram of an optional master cylinder cleanout screenof the user-interface of FIG. 1.

FIG. 4 is a block diagram of an optional safety screen of theuser-interface of FIG. 1.

FIG. 5 is a block diagram of an optional test result input screen of theuser-interface of FIG. 1.

FIG. 6 is a block diagram of an optional system prime menu of theuser-interface of FIG. 1.

FIG. 7 is a block diagram of a fluid-distribution system of theuser-interface of FIG. 1.

FIG. 8 is a block diagram of a brake flush help menu of theuser-interface of FIG. 1.

FIG. 9 is a block diagram of a brake flush status screen of theuser-interface of FIG. 1.

FIG. 10 is a block diagram of a event notification screen of theuser-interface of FIG. 1.

FIG. 11 is a block diagram of a second brake status screen.

FIG. 12 is a block diagram of a scantools interface.

FIG. 13 is a flow chart illustrating a brake flush algorithm utilizingthe fluid-distribution system of FIG. 1.

FIG. 14 is a block diagram illustrating a fluid-distribution systemincluding one or more pumps, a first, second, and third distributionnode, a plurality of three-port valves, and a plurality of bleed/flushlines according to the invention.

FIG. 15 is a table indicating the status of the pumps and three-portvalves of the fluid-distribution system illustrated in FIG. 15 duringvarious disparate procedures.

FIG. 16 is a block diagram illustrating the fluid-distribution system ofFIG. 15 with an additional fluid-distribution node to facilitate primingthe fluid-distribution system and specifically the bleed/flush lines.

FIG. 17 is a block diagram illustrating an optional fourth distributionnode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention is based on the idea of using a fluid-distribution systemto selectively flush brake lines, master cylinders, and anti-lock brake(“ABS”) systems or other hydraulic brake components in a vehicle. Forthe purposes of this application, bleed lines, flush lines, andbleed/flush lines are used interchangeably. Additionally, a manifold ordistribution node is used interchangeably to refer to a volume includingmultiple ports. A three-port valve is used herein to indicate a valvethat includes at least three ports. A common port may alternatively beconnected to either of the other two ports. Connections may be made fromthe fluid-distribution system to the vehicle via the vehicles bleedvalves and master cylinder, referred to herein as discrete fluid-flowelements.

Referring to figures, wherein like parts are designated with the samereference numerals and symbols, FIG. 1 is a block diagram illustrating afluid-distribution system 10 including one or more pumps 12, 13, aplurality of fluid distribution nodes 14, a computing device 16, auser-interface 18, a waste receptacle 20, and a plurality of bleed/flushlines 22 and vacuum lines 23. The primary purpose of thefluid-distribution system 10 is to introduce new brake fluid into amaster cylinder and brake lines of a vehicle in a manner designed toforce air and contaminated brake fluid out of the master cylinder,calipers, or other hydraulic brake components and brake lines. To aid inthe evacuation of air and contaminated fluid, the vehicle's brake linestypically include bleed valves. Modern vehicles may also includeanti-lock braking systems (“ABS”) for varying the pressure of the brakefluid delivered to each brake caliper located at each wheel. These ABSsystems may also include bleeder valves for evacuating air andcontaminated brake fluid from the ABS system. The pumps 12, 13 are usedto provide positive pressure and/or a vacuum to the plurality of fluiddistribution nodes 14.

Various vehicle manufacturers recommend specific brake flush sequencestailored to different makes and models. Using the brake flush machine10, isolated brake flush procedures may be performed according to adesired sequence. Independent control of each solenoid valve 28 allowsthe brake flush machine 10 to isolate individual brake lines, ABSsystems, and the master cylinder during the flush procedure. In thisway, the fluid-distribution system 10 may better flush air andcontaminants from specific portions of the vehicle's brake system.

The computing device 16 may be an embedded processor. Alternatively, thecomputing device may be a micro-processor, a field-programmable gatearray (“FPGA”), an application-specific integrated circuit (“ASIC”),general purpose computer (“CPU”), or programmable logic device (“PLD”).The user interface 18 (FIG. 1) preferably includes a video display 19such as a cathode ray tube (“CRT”) or computer monitor or any of avariety of graphical touch screens. The user interface 18 may alsoinclude an input device such as a keyboard 42 or keypad, a mouse 44, ora touch-screen monitor 46. Alternatively, the user interface 18 mayinclude a set of graphics and textual information, lamps, light-emittingdiodes (“LEDs”), buttons, and switches.

In one embodiment of the invention, the user interface 18 illustrated bythe block diagram of FIG. 2 includes a graphical user interface (“GUI”)50 including information display screens 52, menus 54, and selectableareas or graphical buttons 56. The graphical user interface 50 is avisual representation of a software application 57 stored in a memorydevice 17 and accessed by the computing device 16 of FIG. 1. If thevideo display 19 includes a touch-screen monitor 46, a user may select adisplayed item from one of the menus 54 or one of the graphical buttons56 simply by placing an object or finger in the general area of thedisplayed item. Alternatively, a user may move a graphical cursor orpointer to the desired location using the keyboard 42 or mouse 44 anddepress a switch to indicate the intended choice.

The display screen 52 of FIG. 3 is the main menu 57 of the preferredembodiment of the graphical user interface 50 of the fluid-distributionsystem 10 including graphical buttons for master cylinder cleanout 58,master cylinder fill 60, utilities 62, help 64, and brake flush 66.Selecting the master cylinder cleanout graphical button 58 invokes theinformation display screen 52 of the master cylinder cleanout menu 68 asillustrated by the block diagram of FIG. 4.

The master cylinder cleanout menu 68 includes graphical buttons 56 andadditional textual information 70 to assist a user in using the brakeflush machine 10 properly. Once an activity as been selected, such asinitiating a master cylinder cleanout procedure by selecting the startbutton 72, optional information screens may be displayed. In FIG. 5, theoptional information safety screen 74 includes textual information 70and a graphical compliance indicator button 76 for affirming compliancewith proper safety procedure. The fluid-distribution system 10 may beadapted to prevent a user from continuing a brake flush procedure untilhe has positively indicated his compliance.

Additionally, optional data input screens such as the stripdip menu 78of FIG. 6 may require that a technician or other user input specificinformation before proceeding with a brake flush procedure. Here, thestripdip menu 78 includes graphical buttons 56 for indicating theresults of a stripdip test that gauges the amount of contaminants in avehicle's brake system. This information may be used by thefluid-distribution system 10 to adjust the length of time dedicated to abrake flush procedure. A lower contaminant level may allow for a moreperfunctory brake flush, while a high contaminant level may require amore extensive brake flush procedure. The system prime menu 80illustrated by the block diagram of FIG. 7 includes textual information70 and graphical buttons 56 for initiating or bypassing a primingprocedure.

Once all information safety screen and data input screens have beenmanaged properly, the computing device 16 will initiate a procedure suchas priming the sequential control valve manifold 14, evacuating a mastercylinder, or flushing contaminants from a vehicle's brake lines. This isaccomplished by the computing device 16 sending control signals to thepumps 12, 13 and the solenoid valves 28 (FIG. 1). By regulating whichpumps are operative and which solenoid valves are open or closed, thefluid-distribution system 10 can perform any of a multitude of brakeflush procedures, as previously indicated.

Referring back to the main menu 57 illustrated by FIG. 3, selecting thebrake flush graphical button 66 invoke the brake flush menu 82illustrated by FIG 8. Selecting the help graphical button 84 invokes thebrake flush help menu of FIG. 9 which includes additional textualinformation 70 to aid a technician in the proper use of thefluid-distribution system 10.

The block diagram of FIG. 10 indicates a brake flush status screen 88including a dynamic graphical status display 90 and a stop graphicalbutton 92 for interrupting a brake flush procedure. Event notificationscreens 94, such as the one illustrated in FIG. 11, are displayed whenthe computing device 16 detects an anomalous condition and temporarilyinterrupts a brake flush procedure. In this example, a user may eitherterminate the brake flush procedure, resume the procedure, or correctthe problem and resume the procedure. A second brake flush status screen96, as illustrated by the block diagram of FIG. 12, includes additionaltextual information 70 and graphical buttons 56 for completing a brakeflush procedure.

Selecting the utilities graphical button 62 (FIG. 3) from the main menu57 may invoke optional procedures such as a scan tool interface 98, asillustrated in FIG. 13. Vehicle manufactures sometimes develop automateddiagnostic applications called scantools. The fluid-distribution system10 is designed to interface with these scantools. In an exemplaryinterface of the invention with scantools, a scantool will prepare thevehicle's engine and brake controller for a brake system flush. Usinginput signals from the scantool application, the computing device 16 mayprompt the user to flush new brake fluid through isolated branches ofthe vehicle's brake system according to a sequence and schedule dictatedby the manufacturer.

Vehicle manufacturers have created a protocol for communicating with thevehicle's computer. The tool used to communicate with the vehiclecomputer is commonly referred to as a scan tool. A scan tool may also bebidirectional, meaning it can directly control or initiate procedures.One such procedure is preparing the ABS system for bleeding andflushing.

FIG. 14 is a flow chart illustrating a brake flush algorithm 100utilizing the brake flush machine of FIG. 1. In step 102, a userinitiates a closed-circuit priming procedure. In step 104, the userselects a brake flush procedure such as master cylinder cleanout, mastercylinder fill, or brake flush. Optional steps 106 and 108 includeacknowledging proper safety procedures and inputting test result data,respectively. In step 110, the computing device 16 initiates a brakeflush procedure by selectively activating pumps 12, 13 and opening ports34 and alternate ports 35. In optional step 112, abnormal conditionssuch as low pressure or low fluid flow are displayed as eventnotifications screens and in step 114, completion procedures aredisplayed for the technician.

Other features of the fluid-distribution system 10 include the abilityto transfer contaminated brake fluid from the waste receptacle 20, testthe pumps 12, 13, and troubleshoot problems with the solenoid valves 28.Additionally, the fluid-distribution system 10 may be integrated with abrake flush accelerator as described in U.S. patent application Ser. No.10/981,060 which is hereby incorporated by reference.

In one embodiment of the invention, as illustrated in FIG. 15, afluid-distribution system 200 includes a first distribution node 202connected to a first plurality of three-port valves 204, 206, 208, 210,212, 214. These three-port valves may include solenoid valves thatcreate a first path for fluid flow from their top ports 204 a, 206 a,208 a, 210 a, 212 a, 214 a and their common ports 204 b, 206 b, 208 b,210 b, 212 b when the solenoid valves are not energized. In thisembodiment of the invention, the first paths may be closed off andsecond paths created from the common ports to the bottom ports 204 c,206 c, 208 c, 210 c, 212 c, 214 c which are, in turn, connected to asecond distribution node 216 when the solenoid valves are energized. Asecond plurality of three-port valves 218, 220 connect the seconddistribution node 216 to a third distribution node 222.

A new fluid container 224 is connected to a first pump 226 which is, inturn, connected to the common port 218 b. The common port 220 b isconnected to a second pump 228 which is connected through an optionalthree-port valve 231 for expelling brake fluid from the system to thefirst distribution node 202.

The common port 214 b is connected to a waste container 230 that storescontaminated fluid during normal use. When it is desirable to empty thewaste container 230, the waste container 230 may be purged through thefluid-distribution system 200 and expelled through the optionalthree-port valve 231. Alternatively, the waste container 230 may bedrained or poured into a container which is external to thefluid-distribution system 200.

The common ports 204 b, 206 b, 208 b, 210 b are connected by bleed/flushlines 22 to a vehicles bleeder valves (also not shown). The common port212 b is optionally connected to a vehicle's ABS system (not shown). Thethird distribution node 222 is connected by an optional master/cylinderadapter 232 to a vehicle's master cylinder 234 Alternatively, themaster/cylinder adapter 232 may be replaced with an evacuate gun 236designed to suck fluid and contaminants from the master cylinder

Using this fluid-distribution system 200, an operator may perform avariety of functions without having to reconfigure hoses and bleed/flushlines, as illustrated in the table of FIG. 16. In the first row, thevalves of the brake flush machine are configured so that an operator mayevacuate a vehicle's master cylinder. First, the evacuate gun 236 isplaced on a bleed/flush line 22 attached to the third distribution node222. Solenoid 220 is not energized, creating a path from the thirddistribution node 222 to the second pump 228. Solenoid 214 is energizedcreating a path from the first distribution node 202 to the wastecontainer 230. The second pump 228 is turned on. In this manner, avacuum is created at the master cylinder 234 which pulls brake fluid andcontaminants from the master cylinder, through the evacuate gun 236,through the third distribution node 222, solenoid 220, the second pump228, the optional three-port valve 231, the first distribution node 202,the solenoid 214, to the waste container 230. It is noted forcompleteness that solenoids 204, 206, 208, 210, 212, 216 are energizedand the first pump 226 is turned off removing the associated bleed/flushlines, the vehicle's bleeder valves, and the new fluid container 224from the evacuation procedure.

The second row of the table of FIG. 16 indicates the procedure forfilling the master cylinder 234 with new brake fluid from the new fluidcontainer 224. The first pump 226 is turned on drawing new fluid fromthe new fluid container 224 through the non-energized solenoid 218, thethird distribution node 222, and the master/cylinder adapter 232 to themaster cylinder. This procedure may also be used to flush a mastercylinder when it is disconnected from the vehicle, as in a bench bleed.

To flush a single brake line on the vehicle, the procedure of the thirdrow is implemented. The first pump 226 is on, drawing new fluid from thenew fluid container 224 through the solenoid 218, through the thirddistribution node 222, to the vehicles master cylinder. The fluid isforced through the vehicles brake system, through a bleed/flush line 22,through the solenoid 204, the first distribution node 202, and anothersolenoid 214 to the waste container 230. Likewise, flushing a vehicle'sother brake lines and ABS system, if present, are illustrated in rowsfour through seven. To flush all of the vehicles brake lines and ABSsystem simultaneously, the procedure of row 8 is used.

To empty contaminated fluid from the waste container 230, the procedureillustrated in the ninth row is implemented. Solenoids 214, 220 areenergized and the second pump 228 is active drawing the contaminatedfluid through solenoid 214, the second distribution node 216, thesolenoid 220, the second pump 228, and the three-port valve 231. In thisinstance, the three-port valve 231 is turned so as to expel (“expel”)the fluid from the system, rather than allowing it to pass through(“P/T”).

The tenth row of the table of FIG. 16 illustrates a procedure forvacuuming fluid from the brake lines. In this instance, the first pump226 is on, pumping new fluid from the new fluid container 224 throughsolenoid 218, through the third distribution node 222, and into themaster cylinder 234. The fluid is forced through the vehicle's brakelines (not shown) and is extracted from the bleeder valves by a vacuumcreated by the second pump 228. Here, the second pump draws the brakefluid through solenoid valves 204, 206, 208, 210, 212, through thesecond distribution node 216, and the solenoid valve 220. The fluid isthen forced into the first distribution node 202 and solenoid valve 214into the waste container 230. This procedure may be alternativelyperformed without the aid of the pressure supplied by the first pump226, as well.

Row 12 of FIG. 16 illustrates a cross-flush process where fluid isintroduced into a line and extracted from another line. The second pump228 simultaneously applies vacuum to the second distribution node 216and pressurizes the first distribution node 202 in order to pressurizesome lines while simultaneously applying vacuum to others. For example,new brake fluid may be introduced through the first pump 226, solenoidvalve 218, and the third distribution node 222. This fluid is evacuatedthrough solenoid valves 204, 208, 210, 212 (but not 206), partlyrecirculated through solenoid valve 206 to cross-bleed through thevehicle and partly sent to the waste container 230 through solenoidvalve 214. Many variations of this cross-bleed process may be used topressurize and vacuum individual wheel lines. Alternatively, thisprocess may be executed with the first pump 226 off.

Row 13 of the table of FIG. 16 illustrates an alternate cross bleedprocedure. New brake fluid may be introduced into the vehicle throughthe first pump 226, solenoid valve 218, the second distribution node216, and solenoid valve 204. This fluid is evacuated through solenoidvalves 206, 208, 210, 212 and the first distribution node 202 and sentto the waste container 230 through solenoid valve 214.

If the second pump is powered on during the alternate cross bleedprocedure, a vacuum is applied to the master cylinder through the thirddistribution node 222. The fluid extracted from the master cylinder willbe sent to the first distribution node 202 where it is combined with thefluid arriving through solenoid valves 206, 208, 210, 212 and sent tothe waste container 230 through the solenoid valve 214.

An optional fourth distribution node 240 is shown in the illustration ofFigure 17. Here, the bleed/flush lines are connected from the commonports 204 b, 206 b, 208 b, 210 b, 212 b to the fourth distribution node240 and the priming procedure of the fourteenth row of the table of FIG.16 is implemented to prime the fluid-distribution system 200 and thebleed/flush lines 22 with new fluid. Solenoid 218 is not energized andthe first pump 226 is activated, drawing new brake fluid from the newfluid container 224 into the third distribution node 222. A hose 242connects the third distribution node 222 to the fourth distribution node240, allowing the new fluid to flow to the bleed/flush lines 22, throughthe solenoids 204, 206, 208, 210, 212, through the first distributionnode 202, through solenoid 214, to the waste container 230. A valveprevents outflow through the bleed/flush line for the waste cylinder.

All of these procedures may be facilitated by either removing the checkvalves 36 or using an improved check valve 36. While a traditional checkvalve maybe used to prevent fluid from flowing from the line as it isremoved from the wheel and dropped to the floor, a specialized checkvalve may prevent reverse fluid flow only when under low pressure. Forexample, this improved check valve may prevent reverse flow untilpressure reaches 1 or 2 psi and then becomes unseated, allowing reversefluid flow.

Those skilled in the art of making fluid-distribution system may developother embodiments of the present invention. However, the terms andexpressions which have been employed in the foregoing specification areused therein as terms of description and not of limitation, and there isno intention in the use of such terms and expressions of excludingequivalents of the features shown and described or portions thereof, itbeing recognized that the scope of the invention is defined and limitedonly by the claims which follow.

I claim:
 1. A fluid-distribution system for a brake-flush machine,comprising: a first manifold, a second manifold, and a third manifold; aplurality of first lines adapted for coupling to discrete fluid-flowelements; a plurality of first valves for alternatively placing each ofsaid plurality of first lines in fluid communication with the firstmanifold or the second manifold, wherein the valves are soleniod valvescoupled with the manifolds; a first pump connecting a source of fluid tothe third manifold; a second line connecting the second and firstmanifolds; a third line for coupling the third manifold to an additionaldiscrete fluid-flow element; a computing device configured toindependently control said solenoid valves; a memory device; and agraphical user interface operably connected to said computing device andthat is configured to provide a scan tool interface with said brakeflush machine.
 2. The system of claim 1, further including an additionalfirst line connecting the system to a waste disposal unit.
 3. The systemof claim 2, further including an additional first valve foralternatively placing said additional first line in fluid communicationwith the first manifold or the second manifold.
 4. The system of claim2, wherein said discrete fluid-flow elements include bleeder valves andan anti-lock valve of a vehicle's brake system, and said additionaldiscrete fluid-flow element is the vehicle's master cylinder.
 5. Thesystem of claim 1, further including a second valve coupled to saidsecond line for alternatively placing the second manifold or the thirdmanifold in fluid communication with the first manifold.
 6. The systemof claim 5, further including a second pump in said second line, saidsecond pump being adapted to pressurize the first manifold.
 7. Thesystem of claim 1, further including a third valve coupled to said firstpump for alternatively placing the first pump in fluid communicationwith the second or third manifold.
 8. The system of claim 1, whereinsaid discrete fluid-flow elements include bleeder valves and ananti-lock valve of a vehicle's brake system, and said additionaldiscrete fluid-flow element is the vehicle's master cylinder.
 9. Thesystem of claim 1, further including a second pump in said second line,said second pump being adapted to pressurize the first manifold.
 10. Thesystem of claim 1, further including an additional valve in said secondline, said additional valve being adapted to expel fluid from thesystem.
 11. The system of claim 1, wherein said first, second and thirdmanifolds are part of an integral structure.
 12. The system of claim 1,further including a fourth manifold adapted for fluid coupling to atleast some of said first plurality of lines and to said third manifold.13. The system of claim 1, further including an additional first valvefor alternatively placing an additional first line in fluidcommunication with the first manifold or the second manifold; a secondvalve coupled to said second line for alternatively placing the secondmanifold or the third manifold in fluid communication with the firstmanifold; a third valve coupled to said third line for alternativelyplacing the first pump in fluid communication with the second or thirdmanifold; a second pump in said second line, said second pump beingadapted to pressurize the first manifold; and an additional valve insaid second line, said additional valve being adapted to expel fluidfrom the system; wherein said first, second and third manifolds are partof an integral structure.
 14. The system of claim 13, further includinga fourth manifold adapted for fluid coupling to at least some of saidfirst plurality of lines and to said third manifold.
 15. A method offlushing a vehicle's brake system comprising the following steps:providing a brake-flush machine that includes a first manifold, a secondmanifold, and a third manifold; a plurality of first lines adapted forcoupling to bleeder valves of a vehicle's brake system; a plurality offirst valves for alternatively placing said plurality of first lines influid communication with the first manifold or the second manifold,wherein the valves are solenoid valves coupled with the manifolds; afirst pump connecting a source of fluid to the third manifold; a secondline connecting the second and first manifolds; a third line forcoupling the third manifold to a master cylinder of the vehicle's brakesystem; an additional first line connecting the system to a wastedisposal unit; a computing device configured to independently controlsaid solenoid valves; a memory device; and a graphical user interfaceoperably connected to said computing device and that is configured toprovide a scan tool interface with said brake flush machine; connectingsaid plurality of first lines to said bleeder valves of the vehicle'sbrake system; connecting said third line to said master cylinder of thevehicle's brake system; operating said plurality of first valves toprovide fluid connection between the first manifold and at least one ofsaid bleeder valves of the vehicle's brake system and between the secondmanifold and the balance of said bleeder valves; and activating saidfirst pump.
 16. The method of claim 15, further including the steps ofproviding an additional line adapted for coupling to an anti-lock valveof the vehicle's brake system and an additional valve for alternativelyplacing the additional line in fluid communication with the firstmanifold or the second manifold, connecting the additional line to saidanti-lock valve, and operating said plurality of first valves and saidadditional valve to provide fluid connection between the first manifoldand at least one of said bleeder and anti-lock valves of the vehicle'sbrake system and between the second manifold and the balance of saidbleeder and anti-lock valves.
 17. The method of claim 15, furtherincluding the step of providing a second pump in said second line, saidsecond pump being adapted to pressurize the first manifold; andactivating said second pump.
 18. The method of claim 17, furtherincluding the steps of providing an additional line adapted for couplingto an anti-lock valve of the vehicle's brake system and an additionalvalve for alternatively placing the additional line in fluidcommunication with the first manifold or the second manifold, connectingthe additional line to said anti-lock valve, and operating saidplurality of first valves and said additional valve to provide fluidconnection between the first manifold and at least one of said bleederand anti-lock valves of the vehicle's brake system and between thesecond manifold and the balance of said bleeder and anti-lock valves.19. A method of bleeding a vehicle's brake system comprising thefollowing steps: providing a brake-flush machine that includes a firstmanifold, a second manifold, and a third manifold; a plurality of firstlines adapted for coupling to bleeder valves of a vehicle's brakesystem; a plurality of first valves for alternatively placing saidplurality of first lines in fluid communication with the first manifoldor the second manifold, wherein the valves are solenoid valves coupledwith the manifolds; a first pump connecting a source of fluid to thethird manifold; a second line connecting the second and first manifolds;a third line for coupling the third manifold to a master cylinder of thevehicle's brake system; a second pump in said second line, said secondpump being adapted to pressurize the first manifold; an additional valvefor connecting the system to a waste disposal unit downstream of saidsecond pump; a computing device configured to independently control saidsolenoid valves; a memory device; and a graphical user interfaceoperably connected to said computing device and that is configured toprovide a scan tool interface with said brake flush machine; connectingsaid plurality of first valves to said bleeder valves of the vehicle'sbrake system; operating said plurality of first valves to provide fluidconnection between the second manifold and said bleeder valves of thevehicle's brake system; and activating said second pump.
 20. The methodof claim 19, further including the steps of providing an additional lineadapted for coupling to an anti-lock valve of the vehicle's brake systemand an additional valve for alternatively placing the additional line influid communication with the first manifold or the second manifold,connecting the additional line to said anti-lock valve, and operatingsaid plurality of first valves and said additional valve to providefluid connection between the first manifold and at least one of saidbleeder and anti-lock valves of the vehicle's brake system and betweenthe second manifold and the balance of said bleeder and anti-lockvalves.
 21. The method of claim 20, further including the step ofconnecting one of said plurality of first valves to said anti-lock valveof the vehicle's brake system.
 22. The method of claim 19, furtherincluding the step of connecting one of said plurality of first valvesto said anti-lock valve of the vehicle's brake system.